The present invention relates to a method and a device for producing a transponder, and to a transponder itself that comprises an integrated circuit chip and a coil, wherein the chip and the winding of the coil are positioned approximately in the same plane.
Certain problems are appearing at the time of making such components, caused mainly by the small dimensions of the transponder, the coil, and the integrated circuit chip or the encapsulated integrated circuit die. Normally, electronic elements used for manufacturing transponders are in the dimensions of some hundreds or tens micrometers. The wire used for making the coil is normally in the dimension of ten micrometers so that the diameter of the wire is comparable with the dimension of a human hair.
Before bonding or soldering the several components together they have to be brought in the right position. For this step in the manufacturing process a very precise and exact positioning is needed.
Normally, when producing such transponders or electronic devices the electronic circuits, integrated circuit dice or chips are fixed to a core before winding the latter. The fixing of the chip and the core have to be done with a great precision so that the chip and the core remain in the desirable position. This is of importance to secure that the chip is still exact in its position for locating the ends of the coil above the contact regions of the chip for a correct bonding and contacting after winding the coil around the core with an automatic winding machine.
U.S. Pat. Nos. 5,572,410 and 5,634,261 disclose a process avoiding this fixing process. In the respective described process the electronic circuit is held independently of the winding. First, a wire is guided above a first contact region of the held circuit. Then the coil is wound and after winding the coil the wire is placed above a second contact region of the circuit. Thereafter the wire ends are soldered to the contact regions. The process according to U.S. Pat. Nos. 5,572,410 and 5,634,261 has the disadvantage that the guiding and placing of the wire above the contact regions take place in another plane than that used for winding the coil. Therefore, either the wire has to be handled in three dimensions or the core has to be rotated. Anyway, the process has to take place in three dimensions. This is very elaborate and difficult to perform, resulting in a slow production speed. Furthermore, this kind of process results in high investment in the production line and the produced piece itself is relatively high priced.